DESCRIPTION: (Applicant's Abstract) The specific aim of this project is to use sophisticated meta-analytic techniques to examine the effectiveness of media interventions to reduce youth alcohol, tobacco, marijuana, and illicit drug use. Because of the inherent difficulties in researching media effectiveness and in order to extract as much credible empirical information on this important topic as possible, this meta-analysis will encompass a wider range of relevant research than is generally included in effectiveness meta-analyses. Relying on a patched-up meta-analytic design we will examine the evidence for intervention effectiveness across a variety of media inputs (i.e., source, message, dissemination, supplementation, and recipient) to produce change in a variety of youth outputs (i.e., awareness, knowledge, attitude, and behavior). The primary goal of this synthesis is (a) establishing and rank ordering which media inputs are associated with effective mass-communication for bringing about change in, (b) the awareness, knowledge, attitudes, and behaviors associated with youth substance use and abuse. Secondary goals include, (c) examining the evidence linking changes in the assumed mediators of substance use with changes in the behaviors themselves, and (d) examining the role of research method and procedure in shaping study results. The proposed study exploits existing empirical findings and is expected to advance our understanding of the factors which influence the effectiveness of media interventions to reduce youth substance use.